Impacts of reactive nitrogen on climate change in China
Yalan Shi, Shenghui Cui*, Xiaotang Ju, Zucong Cai & Yong-Guan Zhu*
Impacts of reactive nitrogen on climate change in China
    China is mobilizing the largest anthropogenic reactive nitrogen (Nr) in the world due to agricultural,industrial and urban development. However, the climate effects related to Nr in China remain largelyunclear. Here we comprehensively estimate that the net climate effects of Nr are -100±414 and 322±163 Tg CO2e on a GTP20 and a GTP100 basis, respectively. Agriculture contributes to warming at 187±108and 186±56 Tg CO2e on a 20-y and 100-y basis, respectively, dominated by long-lived nitrous oxide (N2O)from fertilized soils. On a 20-y basis, industry contributes to cooling at -287± 306 Tg CO2e, largely owingto emissions of nitrogen oxides (NOx) altering tropospheric ozone, methane and aerosol concentrations.However, these effects are short-lived. The effect of industry converts to warming at 136±107 Tg CO2e on a100-y basis, mainly as a result of the reduced carbon (C) sink from the NOx-induced ozone effect on plantdamage. On balance, the warming effects of gaseous Nr are partly offset by the cooling effects of N-inducedcarbon sequestration in terrestrial ecosystems. The large mitigation potentials through reductions inagricultural N2O and industrial NOx will accompany by a certain mitigation pressure from limitedN-induced C sequestration in the future.